Blood MALT1 expression could help predict treatment outcomes in psoriasis patients, especially in those receiving biologics

Abstract Introduction Mucosa‐associated lymphoid tissue 1 (MALT1) modulates T helper cell differentiation, pro‐inflammatory cytokine production, and epidermal hyperplasia to participate in the pathology of psoriasis. This study aimed to explore the correlation of blood MALT1 with treatment outcomes in psoriasis patients. Methods MALT1 was detected in peripheral blood mononuclear cells by reverse transcription‐quantitative polymerase chain reaction in 210 psoriasis patients before starting or converting to a new therapy, 50 disease controls, and 50 healthy controls. The psoriasis area severity index (PASI) score was evaluated at month (M)1, M3, and M6 in psoriasis patients. Results MALT1 was increased in psoriasis patients versus disease controls and healthy controls (both p < .001); and positively related to body mass index (p = .019) and PASI score (p < .001) in psoriasis patients. PASI75 rate at M1, M3, and M6 was 22.9%, 46.2%, and 71.0%, respectively; while PASI90 rate at M1, M3, and M6 was 3.8%, 29.0%, and 50.5%, respectively, in psoriasis patients. PASI75/90 rates at M1, M3, and M6 were increased in psoriasis patients receiving biologics versus those without (all p < .05). Pretreatment MALT1 was higher in psoriasis patients who achieved PASI75 (p = .001) and PASI90 (p < .001) at M6 compared to those who did not achieve that. Subgroup analyses discovered that pretreatment MALT1 had a stronger ability to predict PASI75 and 90 realizations in psoriasis patients receiving biologics (area under the curve [AUC]: 0.723 and 0.808) versus those without (AUC: 0.594 and 0.675). Conclusion Blood MALT1 measurement may assist in predicting outcomes in psoriasis patients, especially in those receiving biologics.


| INTRODUCTION
Psoriasis is a chronic autoimmune skin disease that is caused by abnormal keratinocyte proliferation and commonly manifests as itchy rashes and scaly plaques. 1 It is reported that the onset of psoriasis has a distinct bimodal age pattern, with the first and second peaks occurring around 30-39 and 60-69 years, respectively. 2][9][10][11][12] Therefore, exploring potential markers that estimate treatment response is crucial to improve the management of psoriasis patients.
Mucosa-associated lymphoid tissue 1 (MALT1) is a special paracaspase, which has been found to mediate inflammatory and immune responses, thereby participating in the pathology of psoriasis. 13For instance, one study demonstrates that MALT1 forms a complex with B cell lymphoma/leukemia 10 (BCL10) to amplify the keratinocyte responses to several inflammatory cytokines, then stimulate the lymphocytemediated psoriatic skin inflammation. 14Meanwhile, MALT1 regulates T helper (Th) 17 cell and γδ T17 cell differentiation and epidermal hyperplasia to involve in the pathogenesis of psoriasis. 15Moreover, MALT1 regulates the caspase recruitment domain protein (CARD)4-induced production of cytokines and chemokines in keratinocytes, which further causes psoriasis. 168][19][20] However, relevant evidence regarding psoriasis patients is scarce.
The present study aimed to explore the dysregulation of blood MALT1 and its relationship with disease activity and treatment response in psoriasis patients.In addition, 50 disease controls (predominantly atopic dermatitis) and 50 healthy controls (healthy subjects confirmed by physical examinations) were included over the same period, who were included at 35-55 years of age as well as the ratio of 3:2 (male:female) to allow age-sex matching of psoriasis patients.The study had written informed consent from all subjects and approval from the Ethics Committee with the approval number CDCHLL2023-427.

| Collection
The age and gender of all subjects were collected.Besides, the body mass index (BMI), therapy history, and disease characteristics of psoriasis patients were also recorded.For the blood sample, the peripheral blood of psoriasis patients was collected before conversion to a new treatment or start of initial treatment, as well as peripheral blood of disease controls and healthy controls was collected after enrollment.

| Processing
After sample collection, peripheral blood mononuclear cells (PBMCs) were separated, and the MALT1 in PBMCs was detected by reverse transcription-quantitative polymerase chain reaction (RT-qPCR).The kits used were as follows: TRIzol™ Reagent (Thermo Fisher Scientific) for total RNA extraction; PrimeScript™ RT reagent Kit (Takar) for reverse transcription; and THUNDERBIRD® SYBR® qPCR Mix (Toyobo) for qPCR.The internal reference was set as GAPDH.The 2 −ΔΔCt method was used for calculation.The primers were as follows: MALT1 forward: 5′-TCTTGGC TGGACAGTTTGTGA-3′, MALT1 reverse: 5′-GCTC TCTG GGATGTCGCAA−3′; GAPDH forward: 5′-GAGTCCACTG GCGTCTTCAC-3′, GAPDH reverse: 5′-ATCTTGAGGCT GTTGTCATACTTCT-3. 18atients received topical therapy, phototherapy, systemic nonbiologic therapy, or systemic biologics therapy according to the disease status, patient willingness, and the doctor's advice.The data of the current initiating treatment was collected as well.Patients received routine follow-ups for at least 6 months, during which, 30 patients were lost to follow-up or quit the study early (18 had poor efficacy, seven were lost to follow-up, three had adverse reactions, and two quit voluntarily).At the first month (M1), third month (M3), and sixth month (M6), the PASI score was evaluated, and then PASI 75 and PASI 90 were counted.PASI 75 or PASI 90 was calculated as the percentage of patients whose PASI score decreased by 75% or 90% from the time of enrollment.

| Statistical analyses
SPSS version 24.0 (IBM Corp.) and GraphPad Prism version 7.0 (GraphPad Prism) were used for analyses and drawings in the study.Normality was analyzed using the Kolmogorov-Smirnov test.Multigroup comparison analysis was completed using the Kruskal-Wallis H rank sum test or χ 2 test; while two-group comparison analysis was completed using the Wilcoxon rank sum test or χ 2 test.The post hoc comparison was determined using the Bonferroni test.The distinguishing ability was displayed using the receiver operating characteristic (ROC) curve.Factors related to PASI 75 and PASI 90 at M6 in psoriasis patients were assessed by multivariate logistic regression models with forward-stepwise method.p < .05 was indicated as significant.

| Comparison of blood MALT1 among psoriasis patients, disease controls, and healthy controls
Blood MALT1 was the highest in psoriasis patients, followed by disease controls, and the lowest in healthy controls (p < .001).The post hoc comparison revealed that blood MALT1 was increased in psoriasis patients compared to disease controls and healthy controls (both p < .001);meanwhile, blood MALT1 was also elevated in disease controls versus healthy controls (p = .019)(Figure 1A).The ROC curve suggested that blood MALT1 had an acceptable ability to discriminate psoriasis patients from disease controls with an area under the curve (AUC) (95% confidence interval [CI]) of 0.735 (0.659-0.810) (Figure 1B).Notably, blood MALT1 had a good ability to discriminate psoriasis patients from healthy controls with an AUC (95% CI) of 0.879 (0.831-0.928) (Figure 1C).
F I G U R E 1 Blood MALT1 in psoriasis patients, disease controls, and healthy controls.Comparison of blood MALT1 among psoriasis patients, disease controls, and healthy controls (A); the discriminative ability of blood MALT1 between psoriasis patients and disease controls (B), as well as between psoriasis patients and healthy controls (C).MALT1, mucosa-associated lymphoid tissue 1.

| Correlation of blood MALT1 with clinical features in psoriasis patients
Blood MALT1 was positively related to BMI (r = .162,p = .019)and PASI score (r = .260,p < .001) in psoriasis patients.Whereas blood MALT1 was not correlated with other clinical characteristics (all p > .05).Notably, blood MALT1 was also not associated with treatment history, including history of topical therapy (p = .404),history of phototherapy (p = .334),history of systemic nonbiologic therapy (p = .588),and history of systemic biologic therapy (p = .265)(Table 3).

| Correlation of blood MALT1 with PSAI 75 and 90 at M6 in psoriasis patients
Blood MALT1 was increased in psoriasis patients who achieved PASI 75 at M6 compared to those who did not achieve that (p = .001)(Figure 4A).The ROC curve suggested that blood MALT1 only had a weak capability to discriminate patients who achieved PASI 75 at M6 from those who did not achieve that (AUC [95% CI]: 0.643 [0.562-0.742])(Figure 4B).In addition, blood MALT1 was also elevated in psoriasis patients who achieved PASI 90 at M6 versus those who did not achieve that (p < .001)(Figure 4C).The ROC curve revealed that blood MALT1 had an acceptable ability to distinguish patients who achieved PASI 90 at M6 from those who did not achieve that (AUC [95% CI]: 0.725 [0.657-0.792])(Figure 4D).Multivariate logistic regression analysis suggested that blood MALT1 was independently related to achieving PASI 75 (odds ratio = 1.362, p = .002)and PASI 90 (odds ratio = 1.629, p < .001) at M6 in psoriasis patients (Table S1).
Further subgroup analyses found that in patients with current initiating systemic biologic therapy, blood MALT1 had an acceptable ability to discriminate patients who achieved PASI 75 (AUC [95% CI]: 0.723 [0.576-0.870])(Figure 5A) and 90 (AUC [95% CI]: 0.808 [0.704-0.912])(Figure 5B) at M6 from those who did not achieve that.While in patients without current initiating systemic biologic therapy, blood MALT1 could barely discriminate patients who achieved PASI 75 (AUC [95% CI]: 0.594 [0.493-0.696])(Figure 5C) and 90 (AUC [95% CI]: 0.675 [0.582-0.768])(Figure 5D) at M6 from those who did not achieve that.MALT1, as a scaffold protein, plays a fundamental role in immunity and inflammation, which is responsible for the occurrence of various autoimmune diseases. 21Recently, several clinical studies have displayed an increase in MALT1 in autoimmune disease patients. 17,22,23However, rare studies report the dysregulation of MALT1 in psoriasis patients.In accordance with these previous studies, 17,22,23 the present study also figured out that blood MALT1 was increased in psoriasis patients compared with disease controls and healthy controls.The potential reasons could be that (1) MALT1 might regulate the c-Jun pathway to facilitate the hyperproliferation of keratinocytes and the production of chemokines to induce psoriasis. 15(2) MALT1 might also form a complex with BCL10 to initiate psoriatic skin inflammation.As a result, increased blood MALT1 reflected a higher psoriasis risk.The relationship of MALT1 with clinical features in several autoimmune diseases has been revealed by previous studies. 17,18,20According to a study, MALT1 is positively related to C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and clinical disease activity index (CDAI) in CD patients. 17In addition, another study discovers that MALT1 reflects increased disease activity of RA with a positive correlation with CRP, ESR, and Disease Activity Score-28 (DAS28) in RA patients. 18In this study, it was found that blood MALT1 was positively correlated with BMI and PASI score in psoriasis patients.
Regarding BMI, it could be explained by that MALT1 might form a complex with BCL10 and CARD3 to regulate insulin resistance, leading to an increase in BMI. 24,25][16] Systemic biologic therapy has recently received a lot of attention due to its rapid onset of action, safety, and ability to target specific immune system-mediated inflammatory cytokines to attenuate psoriasis activity. 3n this study, several interesting findings regarding systemic biologic therapy in psoriasis patients were disclosed.Firstly, it was found that PASI 75 and 90 rates at M1, M3, and M6 were increased in psoriasis patients with current initiating systemic biologic therapy versus those without that.A potential explanation would be that biological drugs could target TNF-α, IL-17A, and IL-23 to inhibit inflammation, thereby alleviating epidermal proliferation, thickening, and massive desquamation. 26,27ence, PASI 75 and 90 rates were higher in patients with systemic biologic therapy.Secondly, this study discovered that blood MALT1 was elevated in psoriasis patients who achieved PASI 75 and 90 at M6 versus those who did not achieve that.][16] Therefore, elevated blood MALT1 was related to achieving PASI 75 and 90 at M6 in psoriasis patients.Thirdly, from the results of subgroup analyses, blood MALT1 seemed to have a stronger ability to distinguish psoriasis patients with current initiating systemic biologic therapy who achieved PASI 75 and 90 at M6 from those who did not achieve that.This finding might indicate that blood MALT1 might predominantly predict treatment response to systemic biologic therapy, while its ability to predict treatment response to other therapies was relatively weak in psoriasis patients, and the predictive ability of blood MALT1 for whole treatment response was mainly derived from the former.The findings of this study might provide a reference that the early detection of blood MALT1 was meaningful to predict treatment response in psoriasis patients.However, some limitations still existed.(1) The longitudinal change of blood MALT1 was not investigated in this study; however, this would be meaningful to monitor the disease progression of psoriasis patients.(2) This study figured out that blood MALT1 had the potential to predict treatment response to systemic biologic therapy in psoriasis patients, which indicated that blood MALT1 participated in the process of systemic biologic therapy in attenuating psoriasis activity; however, this speculation was warranted to validate.(3) Considering the long-term treatment responses of a proportion of psoriasis patients were unsatisfactory enough, it was meaningful to prolong the follow-up duration to explore the ability of blood MALT1 for predicting long-term treatment response in psoriasis patients.(4) The sample size of this study was inadequate; therefore, the findings of this study might be hard to generalize.
In summary, blood MALT1 may possess the potential to estimate increased disease activity and favorable treatment response, especially to systemic biologic therapy, in psoriasis patients.Considering psoriasis patients require long-term treatments, early detection of blood MALT1 before the initiation of treatments, especially systemic biologic therapy, may be helpful in predicting the therapeutic benefits in these patients.However, restricted by the sample size of this study, the number of patients receiving systemic biologic therapy is much smaller.Therefore, F I G U R E 4 Relationship of blood MALT1 with treatment response in psoriasis patients.Comparison (A) and discriminative ability (B) of blood MALT1 between psoriasis patients who achieved PASI 75 at M6 and those who did not achieve that; comparison (C) and discriminative ability (D) of blood MALT1 between psoriasis patients who achieved PASI 90 at M6 and those who did not achieve that.MALT1, mucosa-associated lymphoid tissue 1; PASI, psoriasis area severity index.
the generalization of this study should be further verified.

2. 1
| Subjects This study consecutively enrolled 210 psoriasis patients between May 2019 and July 2022.Patients who had the following criteria were eligible for enrollment: (a) clinically diagnosed as psoriasis vulgaris; (b) more than 18-year-old; (c) moderate to severe psoriasis with a PASI score ≥8 and the psoriatic area ≥10%); (d) needed to convert a new therapy, or started an initial therapy (for new diagnosis patients); (e) willing to cooperate with follow-up ≥6 months; and (f) were voluntary cooperation in blood collection for study use.Patients who had any following conditions were excluded: (a) diagnosed as pustular psoriasis or erythrodermic psoriasis; (b) complicated with other autoimmune diseases, other skin diseases, or malignant diseases; and (c) pregnant or lactating women.

F I G U R E 2
Relationship of blood MALT1 with current initiating treatment in psoriasis patients.Correlation of blood MALT1 with topical therapy (A), phototherapy (B), systemic nonbiologic therapy (C), regimens of systemic nonbiologic therapy (D), systemic biologic therapy (E), and regimens of systemic biologic therapy (F) in psoriasis patients.MALT1, mucosa-associated lymphoid tissue 1.

F I G U R E 3
Treatment response rates in psoriasis patients.PASI 75 (A) and 90 (B) rates at M1, M3, and M6 in psoriasis patients; comparison of PASI 75 (C) and 90 (D) rates at M1, M3, and M6 between patients with current initiating systemic biologic treatment and those without that; comparison of PASI 75 (E) and 90 (F) rates at M1, M3, and M6 among patients who received adalimumab, ustekinumab, etanercept, infliximab, and secukinumab.PASI, psoriasis area severity index.
Current initiating treatment of psoriasis patients.
T A B L E 2Abbreviations: CyA, cyclosporin A; MTX, methotrexate.
Correlation of MALT1 expression with clinical characteristics in psoriasis patients.Analyzed using Spearman's rank correlation test, the data was displayed by r value and p value.
T A B L E 3 a